Numerical modelling of log dams: A tool for building guidance - proof of concept

Start date

04 January 2021

End date

31 March 2021

Overview

Leaky barriers or log dams are a new, nature-inspired approach to flood management which enhances biodiversity. Log dams mimic the natural wood accumulation in streams which attenuates peak flows downstream by retaining water in the landscape during storms. Being a new approach, there is a clear need for building technical guidance and informing the effective and resilient design of these dams and their location.

The proposed project will develop a proof of concept of a 3D numerical model of log dams. The objective is to demonstrate the interest of the model for simulating a wide range of operational conditions and for building knowledge on the hydraulic functioning of the dams. This new knowledge will inform design aspects affecting their concatenated flood mitigation effectiveness, as well as their stability (e.g. potential scour), maintenance, durability and environmental impacts. The model will be calibrated with the measurements being acquired at the Pipp Brook NFM monitoring site by the Environment Agency and the University of Surrey.

Funding amount

£38,334

Funder

Strategic Priorities Fund

Aims and objectives

Our project addresses the pressing need to build technical knowledge on the hydraulic functioning of log dams, for informing factors affecting their concatenated flood mitigation effectiveness, as well as their stability, maintenance and durability.

The key objectives are to:

Develop a proof of concept of a 3D-Lagrangian model of an existing dam
Demonstrate with a few simulations that the model can reliably simulate the dams’ hydraulics, and hence be used to calculate flow discharge (underneath, between logs, overtop) for different dam configurations and operational conditions
Show that the model allows to identify location of vortices and scour risks
Demonstrate the model’s unique value for simulating and assessing new dam designs.

Watch a 3D simulation of a log dam.